move the figcaption down a bit, fix its height
move the figcaption down a bit, fix its height

gds-attic/transactions-explorer,gds-attic/transactions-explorer,alphagov/transactions-explorer,gds-attic/transactions-explorer,alphagov/transactions-explorer,alphagov/transactions-explorer,alphagov/transactions-explorer,gds-attic/transactions-explorer,gds-attic/transactions-explorer,alphagov/transactions-explorer